On Tue, May 8, 2012 at 9:41 PM, Alejandro Coca Castro <[email protected]> wrote: > Hi Mark, i followed your instructions, so i put in command-line > This > g.region rast=MASK@default nsres=0:00:07.5 ewres=0:00:07.5
will adjust, i.e. modify the resolution in order to fit into the extents. The extents are not modified. In GRASS, the extents have precedence over resolution, unless you use the -a flag, in which case the extents are aligned to the desired resolution. Thus use either g.region rast=MASK@default nsres=0:00:07.5 ewres=0:00:07.5 -a to align the current region to the desired resolution and enforcing this resolution, or g.region rast=MASK@default You can check if the current region is all right with g.region -p or g.region -g, before doing any processing. I tried to set the region with the gdalinfo output of the ArcMap raster fileASC_ARCMAP.asc: g.region w=-60.9250001 e=-49.9979167 n=-0.0000001 s=-10.0000001 res=0.00208333333 Output of g.region -g: n=-1e-07 s=-10.0000001 w=-60.9250001 e=-49.9979167 nsres=0.00208333333333333 ewres=0.00208333334604385 rows=4800 cols=5245 cells=25176000 As you can see, the resolution needed to be adjusted, i.e. there are floating point rounding errors in fileASC_ARCMAP.asc. Using rounded DD:MM:SS.S format: g.region w=60:55:30W e=49:59:52.5W n=0 s=10S res=00:00:07.5 Output of g.region -g: n=0 s=-10 w=-60.925 e=-49.9979166666667 nsres=0.00208333333333333 ewres=0.00208333333333333 rows=4800 cols=5245 cells=25176000 This is probably the desired extents and resolution, the resolution did not need to be adjusted (0.00208333333333333 = 00:00:07.5) . Markus M > > Now, I get the same number of columns and rows. However, the cell size isn't > the same that ArcMAP output file...so i think it can be the reason of > non-similar extend and origin.... > > Below i show you the output gdalinfo, > > Driver: AAIGrid/Arc/Info ASCII Grid > Files: D:\gras_data\temp\test5.asc > > Size is 5245, 4800 > Coordinate System is `' > Origin = (-60.924999999999997,-0.001600000000000) > Pixel Size = (0.002083000000000,-0.002083000000000) > Corner Coordinates: > Upper Left ( -60.9250000, -0.0016000) > Lower Left ( -60.9250000, -10.0000000) > Upper Right ( -49.9996650, -0.0016000) > Lower Right ( -49.9996650, -10.0000000) > Center ( -55.4623325, -5.0008000) > Band 1 Block=5245x1 Type=Int32, ColorInterp=Undefined > NoData Value=-9999 > > Do you have others ideas? > ------ > > Jacquie, thanks for your comments, i hope the next SPs versions fix these > kind of bugs. > > regards, > > 2012/5/8 Alejandro Coca Castro <[email protected]> >> >> Hi, i tried to convert the following enviroments settings to GRASS >> g.region and r.mask for the next ARCGIS output (ASCII file): >> >> fileTIF = r"x:\test\fileTIF.tif" >> MASK = r"x:\test\mask_file" >> env.extent = fileTIF >> env.snapRaster = MASK >> env.mask = MASK >> fileGRD = r"x:\test\fileGRD" >> outCon = Con(fileTIF, fileTIF, "", "VALUE >= 0") >> outCon.save(fileGRD) >> fileASC = r"x:\test\fileASC.asc" >> env.workspace = fileGRD >> RasterToASCII_conversion(fileGRD,fileASC) >> >> So, i put on the GRASS command-line: >> >> r.mask input=mask_file@default >> g.region rast=fileTIF@default res=0.00208333333 align=MASK@default >> r.mapcalc fileGRD = if(fileTIF@default < 0 , null(), fileTIF@default) >> r.out.arc input= fileGRD@default output=x:\test\fileASC_grass.asc >> >> However, the ArcGIS and GRASS outputs had a different extend and curiously >> the GRASS output didn't snap their cells with the MASK. Also, when i observe >> the GRASS output cellsize, it only has the first 6 decimals (f.e. >> 0.002083).... >> >> Finally i tried to setup the parameters of g.region with the ArcGIS output >> but GRASS output definetly didnt have the same properties of ArcGIS output >> (cellsize, columns and rows, extend) >> >> If somebody knows how can i fix it, i'll be grateful, >> >> Thanks in advance, >> >> Alejandro > > > > > -- > Alejandro Coca Castro _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
